Both HIV-infection and drugs of abuse are worldwide health problems and pose significant obstacles for improved disease diagnosis and treatment. We posit that one approach to reach these goals is through proteomics. In this regard, we will use a well developed track record in proteomics research relevant to neurodegeneration and specifically neuroAIDS and apply it to a strategy for useful biomarker discovery that reflect cellular responses to HIV infection and drug abuse, which can be translated to human disease. This aim drives three proposed studies focusing on the theme that methamphetamine (METH) combines with HIV to increase the damaging affect of glial activation on the brain, impairing neurocognitive functions. We will utilize the scientific and technical expertise of three institutions at the University of Nebraska Medical Center (UNMC), the Scripps Research Institute (TSRI), and the University of California San Diego (UCSD) to investigate the interrelationships between drug abuse (with a focus on METH and HIV infection. In project 1, H.E. Gendelman, we will use well-validated in vitro systems to perform mechanistic investigations focusing on the influence of METH on HIV-induced proteomic changes during glial crosstalk and resulting neuronal function. These results will feed directly into the primate studies in projects 2, H. S. Fox, which uses the nonhuman primate model of AIDS and drug abuse, investigating changes in the proteome as well as up-stream gene expression in affected brain tissue for both biomarker discovery and disease pathogenesis. These studies will lead directly into evaluation of clinical specimens proposed in project 3, P. Ciborowski. In this project, biomarker discovery will be performed on plasma from clinical samples of well-characterized individuals, HIV infected, from time points when they are using, or not using, METH. Data from Project 2, examining both the CNS and plasma, will prove essential in selecting candidates. Furthermore, such candidates from these studies, as well as other proteins uncovered from Projects 1 and 2, will be cross-validated in studies of human plasma and CSF analysis. These integrated studies will bring results from cell biology, virology, immunology, and animal pathogenesis to the bedside in attempts to improve care through diagnostic and clinical benefits. There is a high overlap in the population of people who are HIV infected and those who abuse METH. METH use is on the increase in the US. The relevance of this project is that it will result in the discovery of the mechanisms that HIV and METH interact to damage the brain, and identify proteins mark disease processes and serve as targets of therapeutic intervention.